Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
  • B01D21/02—Settling tanks with single outlets for the separated liquid
  • B01D21/08—Settling tanks with single outlets for the separated liquid provided with flocculating compartments
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
  • B01D21/24—Feed or discharge mechanisms for settling tanks
  • B01D21/2405—Feed mechanisms for settling tanks
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
  • B01D21/24—Feed or discharge mechanisms for settling tanks
  • B01D21/2405—Feed mechanisms for settling tanks
  • B01D21/2416—Liquid distributors with a plurality of feed points
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
  • B01D21/30—Control equipment
  • B01D21/34—Controlling the feed distribution; Controlling the liquid level ; Control of process parameters
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/30—Aerobic and anaerobic processes
  • C02F3/301—Aerobic and anaerobic treatment in the same reactor
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2203/00—Apparatus and plants for the biological treatment of water, waste water or sewage
  • C02F2203/002—Apparatus and plants for the biological treatment of water, waste water or sewage comprising an initial buffer container
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2209/00—Controlling or monitoring parameters in water treatment
  • C02F2209/42—Liquid level
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2301/00—General aspects of water treatment
  • C02F2301/06—Pressure conditions
  • C02F2301/063—Underpressure, vacuum
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/02—Aerobic processes
  • C02F3/12—Activated sludge processes
  • C02F3/20—Activated sludge processes using diffusers
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/30—Aerobic and anaerobic processes
  • C02F3/302—Nitrification and denitrification treatment
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W10/00—Technologies for wastewater treatment
  • Y02W10/10—Biological treatment of water, waste water, or sewage

Definitions

• the invention relates to a method for the purification of urban or industrial wastewater in a reactor containing aerobic granular sludge supported or not.
• Unsupported aerobic granular sludge is defined as a community of microbial species aggregated with each other and compact in size between 0.2 and 2 mm, having settling properties significantly faster than conventional activated sludge; the settling rate of the granular sludge in question is at least 10 m / h.
• EP-A-0 849 229 discloses a process employing a two compartment reactor for purifying wastewater using unsupported granular sludge.
• the waste water is introduced into a first compartment of the reactor, while the granular sludge is introduced into a second compartment.
• the two compartments communicate with each other at the bottom.
• An oxygen-containing gas is introduced through the bottom of the second compartment.
• Granular sludge has an upward movement due to sufficiently powerful aeration.
• This sludge passes into the first compartment, unventilated, comprising a submerged separator from which the treated water is extracted.
• This reactor has the advantage of allowing operation in continuous mode. On the other hand, it works with internal re-circulation of granular sludge so that no selection pressure can be exerted to ensure optimal operation with sludge corresponding to the definition of aerobic granular sludge.
• US 6793822 discloses a process for producing granular sludges for use in wastewater treatment. According to this method, a bubble column is used, and the sludge granulation in a wastewater medium requires the following sequence of seven operations to be applied:
• Sludge granulation results from a complex equilibrium between biological and physical phenomena, namely the slow growth of anaerobic biomass, located towards the interior of a granule, and the controlled growth of aerobic biomass simultaneously with the phenomenon of detachment of biofilm, the aerobic biomass being located on the periphery of the granules.
• WO 2004/024638 discloses a method of treating wastewater with aerobic granular sludge operating in three steps: a first consisting of feeding the reactor containing the granular sludge, a second sludge fluidization step through aeration and a third step decantation. This method is also implemented in an air-driven reactor with a height / diameter ratio equal to 20. The industrial application of this process is limited to low sewage flow rates since the maximum construction height generally allowed. is less than 10 m, so that the diameter is limited to about 0.5 m.
• this type of reactor in the aeration phase is like a perfectly mixed reactor.
• the control of the size of the granules is related to the degree of turbulence of the medium which conditions the shear force applied to the granules and the duration of this phase which, moreover, must be compatible with the aerobic biological reaction rates.
• the object of the invention is, above all, to propose an optimized process for the biological purification of wastewater using granular sludge. aerobic, to effectively treat large flows under satisfactory economic conditions.
• Another objective of the invention is to provide an easy-to-use purification system that is easy to scale and adapts to a wide range of flow rates to be treated and to significant variations in water quality to be treated in terms of flow rate. , pollution loads to eliminate.
• the biological wastewater purification process uses a reactor comprising a first and a second compartment communicating with one another at the bottom, the water to be treated arriving in the first compartment, the second compartment containing aerobic granular sludge and being at atmospheric pressure, and an injection of oxygen-laden gas being provided in the lower part of the second compartment, and is characterized in that:
• the granular sludge forms a bed in the second compartment
• the reactor is operated sequentially and discontinuously in a cycle comprising two phases, namely:
• the first compartment is filled under a vacuum with water to be treated
• an injection of oxygen-containing gas takes place in the second compartment, the biological reactions being carried out in an aerobic medium with agitated sludge under the effect of gas injection, the injection of gas is stopped and the granular sludge decant quickly, -
• the treated water is extracted from the second compartment, the shutter of the sludge concentration zone is placed in the open position, then another cycle starts again.
• the aerobic granular sludge is selected by separating the non-agglomerated sludge in the zone of internal concentration in the second compartment, and at the end of the second aerobic phase, the sludge extracted in this concentration zone is emptied.
• the gas injected during the second phase is oxygen, or preferably air.
• the granular sludge may be introduced preformed into the reactor at the beginning of operation, or may be produced in situ in a phase prior to the actual treatment of the wastewater.
• the stirring effect can be assisted by mechanical agitation.
• the flow rate of the effluent from the first compartment to the second compartment when the first compartment is brought to atmospheric pressure is preferably greater than 20 m / h. If the average diameter of the sludge granules tends to decrease, the aeration time, and thus the starvation time of the microorganisms, can be reduced during the aerobic phase to cause an increase in the diameter.
• the durations of the different stages of the cycle can be adjusted to maintain the quality and quantity of granular sludge. For this purpose, it is possible to provide a level sensor for the granular sludge bed whose measurement is taken into account in order to act on the durations of the steps. According to the method of the invention, the maintenance of the quality and performance of aerobic granular sludge is ensured:
• Sludge granulation is determined by the coupling of hydrodynamic regimes suitable for both anaerobic and aerobic phases.
• the sludge is maintained "aerobic granular" by exerting a selection, absent from the process according to
• the invention also relates to a biological waste water treatment plant comprising a reactor with a first and a second compartment communicating with one another at the bottom, the water to be treated arriving in the first compartment, the second compartment containing aerobic granular sludge and being at atmospheric pressure, and an oxygen-charged gas injection means being provided in the lower part of the second compartment, characterized in that:
• the reactor is a batch sequential reactor
• the first compartment is closed at the top and can be isolated from the atmosphere
• the reactor is designed to operate according to a cycle comprising two phases, namely: a first anaerobic phase during which:
• the first compartment is filled under a vacuum with water to be treated
• the two preceding operations are repeated several times in order to introduce and distribute a sufficient volume of effluent in pulsed and sequential mode into the second compartment, the biological reactions being carried out in an anaerobic environment with a bed of sludge pulsed and expanded under the effect of the hydraulic stress of the feed,
• the water supply to be treated is stopped, an injection of oxygen-containing gas takes place in the second compartment, the biological reactions being carried out in an aerobic medium with agitated sludge under the effect of gas injection, the injection of gas is stopped and the granular sludge decant quickly,
• the installation comprises a sludge concentrator located at the outer periphery of the second compartment, on the opposite side to the first compartment and provided with an automated shutter or valve.
• the shutter is closed during the aerobic phase and is open at the end of the aerobic phase to remain open during the anaerobic phase.
• At least one mechanical stirring device is generally arranged in the second compartment.
• the installation may comprise several second compartments associated with the same first compartment to ensure continuous treatment of the wastewater, with means for communicating and / or isolating each second compartment relative to the first compartment.
• Fig.1 is a schematic vertical section of an installation according to the invention
• Fig.2 is a partial schematic section along the line N-II of Fig.1.
• Fig.3 is a schematic top view of an installation with several second compartments associated with the same first compartment, and Fig. 4 is a schematic vertical section of a floating excavator.
• FIG.1 one can see an embodiment of a sewage treatment plant biologically in the presence of aerobic granular sludge according to the invention.
• the installation comprises a batch sequential reactor R provided with an inlet 1 of the effluent in a first compartment 2 feeding, bell-shaped.
• This compartment 2 is closed at the top and can be isolated from the atmosphere.
• a depression can be created in this upper part by means of a fan or a booster working in a vacuum pump 3.
• the level L of the raw water rises progressively in compartment 2 until it reaches a height of 0.6 to 1 m above the water level H of a second compartment 4, or compartment of reaction and separation, which is at atmospheric pressure.
• the height of the first compartment 2 is greater than that of the second compartment 4.
• the general structure of the reactor R corresponds substantially to that of decanters constructed pulsations and marketed by the Applicant Company and described in particular in "Technical Digest Water” 10th edition Degrémont, Volume 2, pages 844-849.
• the implementation and application of the reactor R of the invention totally differ from the settlers in question.
• the compartments 2 and 4 communicate with each other through a passage 2a provided in the lower part of a partition 2b.
• the second compartment 4 contains a bed 5 of granular sludge deposited at the base of the compartment 4 on a grid or a perforated support 5a horizontal.
• the bed 5 is compacted under the effect of gravity.
• An electrical relay (not shown) connected to a level detector 6 controls the sudden opening of a vacuum break valve 7 for placing the upper part of the first compartment 2 in communication with the atmosphere.
• the water then enters the reaction and separation compartment 4 via a pipe 8 on which branch lines 8b which are generally orthogonal to the pipe 8 are connected to ensure a uniform distribution of the water distribution under the bed 5 of granular sludge.
• the overspeed created by the operation of the compartment 2 must be sufficient to allow fluidization of the sludge bed 5
• the bypass lines 8b are provided with devices for ejecting water with a high speed (greater than the minimum speed of fluidization) effecting a flush while tranquilizers 9 ensure the maintenance of a good distribution of the water. liquid through the bed of mud which is loosened and expands by 10 to 30%.
• the non-agglomerated sludge is discharged into a concentrator 10 corresponding to an inclined bottom pit from which they are extracted at regular intervals by a pipe 10a and unrepresented pumping means.
• This type of device has the advantage of being able to purge without risk of affecting the sludge bed.
• the concentrator is also provided with a shutter device (automated valve) 14 for isolating the concentrator in the aeration phase.
• the duration and frequency of the vacuum and flush phases of the first compartment 2 are adjusted to distribute the feed of the effluent over the time necessary for the biological reaction under anaerobic conditions.
• the sludge grows by assimilation of the different substrates, carbon, nitrates and sulphates while the sludge bed 5 is subjected to vertical reciprocating movements and increases in volume.
• the movement of the sludge bed and the creation of interstitial volume promotes the diffusion of substrates and the speed of biological reactions.
• the sludge bed is organized into slices of sludge of different physical properties.
• the densest granular sludge is deposited in the lower layers whereas the non-agglomerated particles corresponding to the granules in formation or deflocculated are distributed on the surface. A classification takes place.
• the concentrator 10 placed in the second compartment makes it possible to recover the granular sludge which does not possess the desired physical characteristics.
• the ramp 11 may be located below or above the water distribution pipes 8, 8b to be treated.
• the shutter 14 Before starting the aerobic phase, the shutter 14 is in the closed position to isolate the concentrator.
• the introduction of oxygen-containing gas takes place at the end of the first phase of the process corresponding to a reaction period in an anaerobic medium while the effluent feed is complete.
• the velocity of the gas injected by the ramp 11 must be sufficient to cause the turbulent movement of the granules necessary to cause the attrition at the origin of the detachment of fast-growing biofilm.
• a suitable mechanical stirring device B in particular with a propeller, can complete the gas injection.
• the gas simultaneously provides the oxygen necessary for the biological reactions of carbon oxidation, nitrification.
• the purified water in carbon, nitrogen, sulphates and phosphorus is extracted via a device 12 such as weir or valve located at the median height of the reactor or by a floating weir 13 (Fig.4) of the shovel type, connected to the treated water outlet by a pipe articulated on a ball joint.
• a device 12 such as weir or valve located at the median height of the reactor or by a floating weir 13 (Fig.4) of the shovel type, connected to the treated water outlet by a pipe articulated on a ball joint.
• the shutter 14 is opened in order to allow the granules to be selected at the beginning of feeding.
• the installation makes it possible to carry out the following sequence necessary to maintain the wastewater treatment system with aerobic granular sludge in a single sludge bed reactor alternately pulsed and stirred, and subjected to selection: Anaerobic phase a) feed in pulsed raw water: fluidization of the sludge bed.
• Aerobic phase b) turbulent suspension or not of the system with injection of gas containing oxygen c) decantation and evacuation of the treated water clarified by drain valve. d) extraction of concentrated sludge in the frequency selector.
• Granular sludge then offers increased performance related to the renewal of the active surface exposed to the substrates to be processed.
• FIG. 3 schematizes a configuration with four second reaction compartments 4a, 4b, 4c, 4d whose communication with the first central compartment is controlled by valves Va, Vb, Vc, Vd.
• the second compartments can be placed in communication with the first compartment in a circular permutation to ensure continuous discharge of treated water on the pipes 12a or 12b which meet downstream.
• the sludge is evacuated by pipes 15a, 15b.
• a reactor was used in which the reaction and separation compartment was square-based with a length of 0.25 m and a useful volume of 0.200 m 3 for a water depth of 3 m.
• the granular sludge with an average diameter of 1.8 mm has a concentration of 13 kg / m 3 .
• the feed compartment 2 has a water level equal to 4 m under vacuum.
• the effluent to be treated was sieved urban waste water, with a temperature of 22 ° C and characterized by concentrations: Total oxygen chemical demand, total COD: 480 mg / L
• the following treatment sequence was applied per 100 L of treated effluent.
• the effluent was admitted at the rate of 30 m / h in the second compartment 4 of reaction in an anaerobic medium for a period of 20 minutes with operating cycles of the first compartment 2, or bell, at 35 s of filling and s hunting.
• NGL 70%.

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• Life Sciences & Earth Sciences (AREA)
• Biodiversity & Conservation Biology (AREA)
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• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Organic Chemistry (AREA)
• Biological Treatment Of Waste Water (AREA)
• Water Treatment By Sorption (AREA)

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• 2007
  • 2007-08-06 FR FR0705735A patent/FR2919859B1/fr not_active Expired - Fee Related
• 2008
  • 2008-07-30 EP EP20080839118 patent/EP2176176B1/de active Active
  • 2008-07-30 PT PT08839118T patent/PT2176176E/pt unknown
  • 2008-07-30 US US12/672,153 patent/US8409440B2/en not_active Expired - Fee Related
  • 2008-07-30 WO PCT/FR2008/001135 patent/WO2009050347A2/fr not_active Ceased
  • 2008-07-30 DK DK08839118T patent/DK2176176T3/da active
  • 2008-07-30 AT AT08839118T patent/ATE512934T1/de not_active IP Right Cessation
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